1. Field of the Invention
This invention relates to a navigation device which, considering conditions of the destination inclusive of the season, time, etc, makes a route searching depending on the conditions, as well as to a method of searching a route.
2. Description of Related Art
FIG. 9 is a block diagram showing the conventional navigation device disclosed in Published Unexamined Japanese Patent Application No. 304505/1999.
Referring to FIG. 9, reference numeral 101 denotes a compact disc read only memory (CD-ROM) which stores therein map data, 102 denotes an operating unit, and 104 denotes a global positioning system (GPS) receiver which receives GPS signals transmitted from GPS satellites to thereby detect the latitude and longitude of the current position of a vehicle. Reference numeral 105 denotes an autonomous navigation sensor, 105a denotes an angle sensor, 105b denotes a travel distance sensor, 107 denotes a display using liquid crystal, 108 denotes a speaker, and 110 denotes a navigation device main body. Reference numeral 111 denotes a buffer memory which temporarily stores therein map display read out from the CD-ROM 101, 112 denotes an interface which sends and receives data between the operating unit 102 and a control unit 116, 114 denotes an interface which sends and receives data inclusive of the latitude and longitude of the current position between the GPS receiver 104 and the control unit 116, and 115 denotes an interface which connects the autonomous navigation sensor 105 and the control unit 116. Reference numeral 117 denotes a category/area setting memory, 118 denotes a map drawing unit, 120 denotes a guide route memory, and 121 denotes a guide route drawing unit. Reference numeral 119 denotes an operating screen/mark generating unit, 122 denotes a voice signal generating unit, and 123 denotes an image composing unit.
The operation of the conventional navigation device will now be described.
This navigation device has a function of searching a route running through a scenic spot and a function of searching for routes such as a travel service for guiding a number of such places in succession. When a user has designated a drop-in guide route searching, it starts searching for candidates for drop-in according to user's preference. If the user has designated a desired facility as a drop-in destination among the candidates for drop-in, the route of the lowest cost among the routes running through the designated facility is searched to adopt it as a guide road.
Since the conventional navigation device is configured as described above, in case a route search is made by setting an ordinary destination other than sightseeing, a search is made for the route through which a user can be reached the destination in the shortest time and at the shortest distance. Therefore, the route running through the scenic spot is seldom searched where the user can enjoy beautiful scenery. In case one wishes to enjoy sightseeing while driving a vehicle, a route through which the user can enjoy the beautiful sceney is not searched unless the setting is manually made of the destination and the passing points.